As a result of the constant progress in the electronic technological fields and the demands of users on the compact design and high operating performance of hand-held electronic devices, such as mobile phones, tablet computers, personal digital assistants (PDAs) and so on, electronic elements in the hand-held electronic devices, such as the central processing unit (CPU) and integrated circuits (ICs), produce a large amount of heat during high-speed operation thereof. The produced heat tends to accumulate in the very limited internal space of the compact electronic devices, and must be timely removed to ensure good operating efficiency and extended service life of the electronic elements.
The currently available hand-held electronic devices usually include a case, a heat-producing element, and a metal-made heat-transfer plate serving as a heat dissipation structure. The case internally defines a chamber for accommodating the heat-producing elements, such as the CPU, various ICs or other electronic parts. The heat-transfer plate is directly attached to one side of each heat-producing element. Heat produced by the heat-producing element is transferred from the heat-producing element to the heat-transfer plate and is finally dissipated into ambient air from the heat-transfer plate. However, the conventional heat-transfer plate designed for the hand-held electronic devices has relatively poor heat dissipation effect. This is because, with the heat-transfer plate directly attached to the heat-producing element, the produced heat tends to accumulate on a high-temperature zone, i.e. areas of the heat-transfer plate that surround the heat-producing element, instead of being distributed over the whole heat-transfer plate. Therefore, the conventional hand-held electronic devices have poor heat dissipation efficiency.
It is therefore tried by the inventor to develop an electronic substrate with heat dissipation structure that has small thickness but upgraded heat dissipation efficiency.